# First project: Garmin Rino GPS/FRS/GMRS?

**URL:** <https://www.ruby-forum.com/t/first-project-garmin-rino-gps-frs-gmrs/234569>\
**Category:** GNU Radio\
**Created:** [March 14, 2015, 1:13am UTC](https://www.ruby-forum.com/t/first-project-garmin-rino-gps-frs-gmrs/234569 "2015-03-14T01:13:35Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [March 14, 2015, 1:13am UTC](https://www.ruby-forum.com/t/first-project-garmin-rino-gps-frs-gmrs/234569/1 "2015-03-14T01:13:35Z")

</div>

Hello,

I’m very new to GNURadio and to RF exploration/hacking in general. I’ve  
downloaded GNURadio on my Linux system and have been successful in  
installing a couple of systems. I got the RTL-SDR USB receiver working,  
and have the gr-rds system working.

A project I thought of working on would be to try to understand and  
document the system used by Garmin Rino GPS/FRS/GMRS systems (see  
[https://buy.garmin.com/en-US/US/cOnTheTrail-cTwowayRadio-p1.html](https://buy.garmin.com/en-US/US/cOnTheTrail-cTwowayRadio-p1.html)). These  
systems seem to transmit the transmitter’s latitude, longitude and  
altitude to all the other Rino radios using the same FRS or GMRS channel  
and squelch code. This seems to occur whenever the Push To Talk button  
is pressed. The receiver’s location, as well as all the other  
transmitters, can be viewed on everyone’s GPS display.

I searched for Garmin and Rino in the mailing list’s archives, and  
didn’t come up with anything significant. Is this idea similar to  
anything else that anyone’s attempted? If not, can anyone point me to  
ideas for getting started? I’m thinking that I’ll first have to capture  
the waveforms produced by keying my Rino, then see if I can discern the  
encoding of the digital information.

Thanks for any pointers anyone can think of to begin working on this  
system.

-Kevin

---

<div class="post-metadata">

**Author:** ![Kevin\_Zembower](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/ecd19e/32.png) [@Kevin\_Zembower](https://www.ruby-forum.com/u/Kevin_Zembower)\
**Post date:** [March 14, 2015, 2:29am UTC](https://www.ruby-forum.com/t/first-project-garmin-rino-gps-frs-gmrs/234569/2 "2015-03-14T02:29:00Z")

</div>

Kevin,

I don’t think there’s anyone doing this. In general, I recommend  
checking the PyBOMBS recipe list which contains a lot of active  
projects.

For how to start, that depends a lot on your comfort level doing  
wireless comms and DSP. Do you have any details on the modulation used?

Cheers,  
m